AVIAN DIGESTIVE ANATOMY Flashcards
carnivore
eat animal material
called “birds of prey” or ‘raptors’
eat live prey or carrion ( dead animal material)
may be considered obligate scavengers –> entirely rely on carrion
Herbivore
eat plant material
very rare for birds
- most are opportunistic omnivores
- supplement the herbivorous diet with insects
head gut
oral cavity–> beak/bill
- prehension of food
- specialized to diet
- not a lot of mechanical digestion
salivary glands
- most birds only have mucus-secreting glands
- some species secrete an adhesive compound to capture prey or build nests
pharynx
esophagus
transfer food from pharynx to crop
allows for controlled regurgutation
- regurgitate crop contents to feed young
- regurgitate undigestible food items from the gizzard
Crop
major site of food storage
site of microbial fermentation for the hoatzin
proventriculus
true stomach
secretes pepsinogen + HCl
secretes mucus
Ventriculus
‘gizzard’
major site for trituration of food (decrease particle size)
thick muscular walls with koilin membrane
gizzard stones (grit)
filter indigestible parts of food
forms pellet to be egested (6-10hrs to form after meal)
Small Intestine: Duodenum
primary site of enzymatic digestion
pancreatic/hepatic secretions
alkaline/mucus secretions (pH balance)
Small Intestine: Jejunum
the primary site of nutrient absorption
villi and microvilli (increase SA)
Small Intestine: Ileum
Vitamin B12 and bile acid absorption
cecum
site of microbial fermentation (VFA, B vitas, Vit K)
- paired (most birds) ‘ceca’
- single (heron)
- functionless (most carnivores)
- absent (swifts, hummingbirds, woodpeckers, budgies)
- more plants in the diet will increase the size of ceca
- have the same issue as hindgut fermenting animals, not able to absorb all of what’s made by microbes
Colon
very few have a distinct colon
only the horned screamer and ostrich have a colon
rectum
the short, straight remainder of the hindgut
water and mineral absorption
cloaca
a combined outlet for fecal/urinary excretion
